Park Tool DCA-1
Best precision measurement attachment for dedicated bicycle mechanics.
This simple attachment transforms standard calipers into specialized tools for measuring brake rotor thickness and chainring bolt patterns. It is an essential, low-cost upgrade for anyone performing precise drivetrain or braking system maintenance.
$18.95
at
Cambria Bike
More Derailleur Hanger Alignment Gauge options
Who it's for
- Mechanics needing exact spacing for bolt patterns or spoke holes
- Tool owners looking to expand the utility of their current calipers
- Professional bike mechanics requiring long-lasting and reliable shop equipment
Who should skip it
- Specialized builders working with non-standard or miniature hardware components
- Technicians who prefer a streamlined tool for quick handheld measurements
- Busy mechanics who prioritize direct-read measurements to save time
Performance breakdown
Rotor Wear Precision
Bypasses unworn edges to reveal true braking surface thickness.
BCD Measurement Accuracy
Conical points make calculating chainring bolt patterns simple and reliable.
Tool Compatibility
Adapts seamlessly to almost any standard caliper currently on your bench.
Build Durability
Rugged steel construction ensures years of reliable service in the shop.
Ease of Setup
Quickly attaches to existing calipers without requiring complex calibration steps.
Versatility
A clever dual-purpose solution that solves two distinct maintenance headaches.
Key Specs
Weight
45.36 grams
Compatibility
Most standard vernier, dial, and digital calipers
Material
Steel
Intended Use
Measuring disc brake rotor wear and bolt circle diameter (BCD)
Number of Pieces
1
Number of Functions
2
Know before you buy
Still have a question?
Ask Metto anything about the Park Tool DCA-1 before you decide.